a. Field of the Invention
This invention relates to the field of miniaturized data input/output and character recognition systems.
B. Prior Art
While miniaturization of electronic circuitry for data storage and processing applications has progressed to a highly sophicated state, the benefits which would otherwise derive from this sophistication have been impeded by the failure of data input/output technology to develop with equal rapidity. This situation has become so extreme that further miniaturization of electronic circuitry will yield no appreciable benefit to numerous product areas employing miniaturized electronic data processing circuitry unless input/output devices first undergo significant improvement. But, unlike the data processing circuitry itself, size reduction of input/output devices is limited primarily by human engineering factors. For example, the size of the standard keyboard could easily be reduced significantly except that convenient human finger tip operation would no longer be possible because the size of the smallest standard data input/output symbols can not be reduced below what the human eye is capable of quickly or easily perceiving. A particular example of this dilemma is in the field of hand held calculators where the minimum size required for a convenient keyboard is the only limitation standing in the way of further reduction in overall size.
To date, most efforts at solving this problem have centered strictly on the hardware technology. For example, one approach has been to replace the standard calculator keyboard with specialized keys, each of which may be pivoted by the human finger in any one of four directions to uniquely indicate one of four character symbols or mathematical operators. By use of five such four-way keys, the size of a normal calculator may be reduced to that of a somewhat oversized writing instrument such as embodied for example in a calculator pen sold under the trademark CALCUPEN available from Chafitz, P.O. Box 2188, Dept. 289, Rockville, Maryland. While a decided improvement over the standard pocket calculator in terms of size, devices which need to accommodate five input switches and a standard visual display necessarily retain a rather bulky appearance and feel compared with a standard hand held writing instrument.
In an alternative attempt to avoid the need for the standard bulky keyboard, specialized writing platens employing sensors for responding to symbolic hand motion or the symbolic motion of hand held instruments have been developed. Examples of this type of input apparatus are disclosed in U.S. Pat. Nos. 3,142,039, 3,253,258 and 3,704,343. Although desirable in some respects, there are numerous drawbacks to devices employing specialized writing platens including the high cost of platens and the required specialized training of the operator. More particularly, devices of this type require motion to occur sequentially over distinct predetermined areas in order to yield electrical output signals properly indicative of the symbolic motion.
In another effort to further refine input apparatus, writing instruments have been developed, such as illustrated in U.S. Pat. No. 3,835,435, which generate electrical signals indicative of visual indicia being formed by the movement of the writing tip of the instrument over an ordinary writing surface. This technique is accomplished by including motion sensing transducers in the tip of the writing instrument. While such instruments normally need to be connected with separate character recognition circuitry by means of flexible wiring, the device disclosed in the U.S. Pat. No. 3,835,453 includes a radio transmitter/receiver and visual display on the writing instrument to permit radio communication with remote character recognition circuitry. Furthermore, the U.S. Pat. No. 3,835,453 discloses an optical display directly on the writing instrument for providing a visual verification that the desired input character symbol has indeed been recognized by the electronic circuitry.
While a device which includes a character recognition circuit remote from an input pen solves some of the bulkiness problems inherent in devices which include such circuitry within the pen, mounting of the display on the pen still imposes constraints on possible further reduction in the size of the writing instrument and impairs accurate reading of the displayed information while the writing instrument is in motion. Through normal usage and custom, humans generally learn to solve mathematic problems and compose written language while employing a writing instrument. Devices which position the character recognition circuitry remotely but retain the display on a pen take limited advantage of this fact but may require cessation of hand movement in order that the visual display can be held in a steady, easily read position.
The use of character recognition circuitry with a hand held writing instrument input is well known and has become highly sophisticated as disclosed in the following U.S. patents. U.S. Pat. Nos. 3,145,367; 3,182,291; 3,462,548; 3,500,323; 3,906,444; 3,930,229; While probably enjoying some specialized success, character recognition circuitry using a hand held writing instrument input has apparently not found wide commercial acceptance and does not vie in popularity with the more common keyboards.
An entirely separate approach to satisfying the need for a more convenient miniaturized data input/output system is disclosed in U.S. Pat. No. 3,955,355 which discloses a wrist mounted unit including an electronic display and keyboard interconnected by horological and calculator circuitry. Devices such as disclosed in U.S. Pat. No. 3,955,355 (and in U.S. Pat. No. 3,937,004 disclosing a wrist mounted body condition monitor) exploit the benefits of convenience and small size of mounting an electronic display on the wrist in the manner of a digital watch. However, from a practical bio-engineering standpoint, devices employing a wrist mounted display unit with a keyboard on the display do not solve the problem of making the input of data convenient for the user. For example, a device which requires both the display and the keyboard to be wrist mounted inherently requires a bulky overall size in order for the user to be able to accurately operate the keyboard.
In short, most efforts at miniaturization of input/output structure for small sized data storage and processing circuitry have centered on the introduction of new hardware technology rather than creating a more bio-compatible input/output system. In privious instances where prior art components have been reorganized, accuracy and ease of operation of either the input or output data processing structure has been compromised.
Significant improvement in products used directly by humans need not derive solely from technological breakthrough. In fact, attention to bio-engineering principles, that is the reorganization of known components to facilitate the ease with which a human interacts with his environment, can produce results every bit as startling as major technological advance.